ANOMALOUS AND ORDINARY HALL EFFECT IN TERBIUM

The anomalous and ordinary Hall coefficients Rs and R 0 defined by the relation ρH≡R 0B+Rs4πM have been obtained for single-crystal Tb in both ordered and paramagnetic states. Results for the component of the Hall resistivity ρH characterized by H (and M) in the basal plane 101̄0 easy axis in Tb) show that ρH is linear in H above TN and exhibits a strong temperature dependence which is almost entirely due to that of the magnetic susceptibility. Rs is found equal to -40.4×10-12 Ω·cm/G and temperature independent. Below TN the anomalous coefficient found from the saturation Hall resistivity reverses sign, passes through a maximum near 140°K (where Rs=+22.4×10-12 Ω·cm/G) and falls to 0 below 30°K. Possible mechanisms for this unique sign reversal in Rs are discussed. The T-independent nature of R s above TN plus a linear dependence of Rs on the derived magnetic resistivity below 120°K indicates that thermal disorder of the 4f spin system is the dominant scattering mechanism in the Hall effect. The normal coefficient is essentially temperature independent above approximately 260°K (R0=-1.0×10-12 Ω·cm/G) and below 90°K. At intermediate temperatures R 0 rises to a positive maximum of +8.8×10-12 Ω·cm/G at 205°K. Hall resistivity data above TN with H along 〈0001〉 directions (second independent component in hcp symmetry) give significantly larger values of Rs and R0 reflecting the Fermi surface anisotropy. © 1969 The American Institute of Physics.